Design for guns employing split chamber



Dec. 30, 1958 v. F. LUCHT DESIGN FOR cums EMPLOYING SPLIT CHAMBER 2 Sheets-Sheet 1 Filed May 1, 1956 .HTTURNE'YE.

Dec. 30, 1958 v. F. LUCHT 2,866,386

DESIGN FOR GUNS EMPLOYING SPLIT CHAMBER Filed May 1. 1956 2 Sheets-Sheet 2 Pressqre -S,aac'e Curve for 77,0105! propel/EH27 Sea! United States DESIGN FOR GUNS EMPLOYING SPLIT CHAMBER Victor F. Lucht, Arlington County, Va., assignor to the United States of America as represented by the Secretary of the Army The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to firearms and more particularly to guns of the type employing a split chamber.

A long recognized development problem in connection with guns of the split chamber type is in the provision of simple, yet effective sealing means to not only seal the chamber, but also avoid battering and indenting the adjacent barrel breech face against which the seal is effected.

To the end of providing a seal in the type of gun indi cated, U. S. Patent 325,878 provides a gas check sleeve having an external annular recess or groove to receive a small portion of the gas generated by the firing of a projectile from the gun to loosen the gas check sleeve and move it forward to bridge the gap between the barrel and the cylinder or drum, with the gas check sleeve being made in two separable substantially semi-cylindrical mating sections so that the sections will be forced apart and fit tightly against the walls of the recess in which it is disposed to prevent the escape of gases between the outer surface of the gas check sleeve and the walls of the recess. A similar construction embodying the same concept of an expandible gas seal sleeve is disclosed in U. S. Patent No. 34,226. In U. S. Patent No. 1,965,637, the problem was solved by providing a tapered counterbore in the adjacent end of the barrel to receive a complementarily shaped end of a gas seal sleeve, along with mechanical means operatively connected to and responsive to the revolution of the drum to import movement of the sleeve forward whereby the tapered end thereof will enter the counterbore of the barrel.

The prior attempts to solve the problem have necessitated such machining operations in the production of the gun that the resultant cost is relatively high. Also, the prior disclosures have not, in addition, solved the avoidance of battering and indenting of the adjacent breech end of the barrel caused by the successive hammering of the gas obturating sleeve end against the adjacent breech face. Such battering and indentations result in ineflicient and inaccurate operation of the gun due to the escape of the powder gas through an ineffective seal.

To overcome the tendency to the battering and indentation of the breech face, the breech face had been hardened by heat treatment. However, this has led to problems in regard to the use of hardening and heat treating processes, as well as introducing additional steps in the production of the gun, adding to its cost of production.

It is therefore the principal object of this invention to provide in the type of gun described, a chamber construction which will form a satisfactory seal between the drum and the gun barrel, entailing a simple production step involving a simple modification of present structures, and which will eliminate the necessity for hardening the adjacent breech face of the barrel.

It is a further object of this invention to provide seal aren't 2,866,386 6 Patented Dec. 30, 1958 tions to thus reduce the impact of the sealing means on the breech face of the barrel.

The above and other objects can be attained by practicing this invention, which incorporates among its features in a gun of the type including a barrel and a drum having projectile holding chambers longitudinally therethrough and in axial alignment with the base of the gun barrel and with one end of the drum in normally spaced relation with the adjacent breech face of the barrel, means for sealing the chamber by bridging said space, the means comprising an obturating sleeve mounted within the chamber for movement longitudinally thereof and through the one end of the drum adjacent the breech face, the chamber being provided with at least one passage extending longitudinally thereof for conducting therethrough gases resulting from the firing of a projectile from the chamber and the gases impinging against the adjacent end of the obturating sleeve to move the sleeve longitudinally of the chamber into sealing relation with the breech face of the barrel and bridge the space between said one end of the drum and the breech face to seal the chamber during the firing of a projectile.

Other objects, features and advantages will become apparent from a consideration of the following detailed description, forming the specification, and taken in conjunction with the accompanying drawings, in which:

Figure 1 is a fragmentary, somewhat schematic, longitudinal cross sectional view of a portion of a gun of the split chamber type, showing the obturating sleeve in its normal or inactive position;

Figure 2 is a fragmentary cross sectional view, similar to Figure l, but showing the sleeve in its active position bridging the space between adjacent faces of the drum and gun barrel;

Figure 3 is a cross sectional view taken along line 3-3 of Figure 1; and

Figure 4 is a view showing the charted pressure characteristics of a typical propellent.

With continued reference to the drawings, there is shown a portion of a drum 10 which may be of the revolvable type and have a plurality of equidistantly spaced projectile carrying chambers, such as chambers 12, arranged concentrically about the axis of the drum and extending longitudinally therethrough to open at opposite ends 14 and 16 thereof.

A typical projectile generally indicated at 18, such as a shell, having a case 26 and a bullet 22 extending from the mouth 24 of the case toward the bore 26 of a gun barrel 28, is held in the chamber 12. The bullet is to be fired therefrom, by the usual firing mechanism (not shown), through the bore 26 which is axially aligned with the chamber 12.

As will be noted from the drawings, the breech face 30 of the barrel is adjacent the end 16 of the drum 10, but is normally spaced therefrom. In order to seal this space when the weapon is fired, a sealing means is required. In the present invention, an obturating sleeve 32 having a bore 34 of the same size and in register with the cham-' ber 12 is disposed in a counterbore 36 in the chamber 12. The counterbore opens through the end 16 of the drum.

The obturating sleeve 32 is mounted for movement longitudinally of the chamber 12, within the counterbore 36 toward the breech face 3d, upon firing of the gun, to bridge-the space .betweenend, 16 and face 30;, Thus, the chamber 12 will be. completely sealed asthe endtf3 of the-sleeve is moved into abutting relation. with. breech face. 30.

In order to'move theobturating sleeve'into the chamber sealing'position, aplurality of longitudinal, circumferentially spaced grooves38, defining passages for the gases resulting from the. firing of'the projectile, is cut into the. chamber 12 at the end thereof adjacent the counterbore 34.-- Each passage. 38 extends. from a location intermediate the ends of the. chamber 12, and increases in.

depth as it recedes from the intermediate chamber location to open into the counterbore. 36-behind the adjacent 611(1'40 of the obturating sleeve 32.- Thus, each passage 38' slopesfrorh, the intermediate. location of the chamber 12, at which locationthe. mouth 24 f the, shellis disposed when the'shell' or projectile 18 is inserted into the chamber, to the juncture of the chamber with the counterbore.

Thus, as, a shell or projectile is fired, the resultant gases will be conducted through the passages 38 to impinge upon the adjacent end 40 of the obturating sleeve. This will force the sleeve to move in arectilinear path longitudina-lly of the chamber and through the end "1-5 thereof into abutting relation with the adjacent breech face 36. The space between the end 33 and face 40 will thus be bridged to provide a' seal for the chamber 12. Therefore, the'seal will be complete and efficient and accurate use of the gun'will be insured.

With reference to Figure 4, it will be observed that the pressure of the powder gases increase rapidly to a maximum, then falls off somewhat more gradually. In present gun structures, the seal sleeve is subjected to the maximum pressure developed in the barrel. This imports a great velocity to the seal sleeve and causes a severe impact of the sleeve against the breech face of the barrel resulting in malformations in the breech face and structural failures of the gun at this point. However, the-present invention utilizes only that portion of the powder gas pressures created occurring between the base or end 14- of the chamber 12 and the mouth 24 of the inserted projectile, which is considerably below the maximum pressure produced within the chamber and barrel. To this end, the simple machining of the slots 38 provide passages to conduct the powder gases under the pressure indicated from the base to the projectile mouth. This gas, under the less than maximum pressure indicated, is sufficient to move the obturating sleeve 32 into sealing relation with the breech face 30, but does not impart such a velocity of movement to the sleeve as to cause damage to the breech faceupon contact therewith. The powder gases, after moving the obturating sleeve will escape from the passages 38 behind the bullet 22 due. to the taper of the passages, yet holdthe seal sleeve in proper sealing relation until the bullet has left the gun.

The grooves 38 may actuallybe considered as metering slots. Since pressure characteristics of different powders will vary, it is possible to so machine the grooves whereby'the slope from zero adjacent the mouth of the projectile to the end opening into counterbore 36 can be changed, as well as the cross sectional area of the slots modified, to meet the corresponding pressure character istics of different propellents or powders.

Thus, it will be appreciated that this invention takes advantage of the pressure characteristics occurring in the chamber and barrel, utilizing less than the maximum pres sure produced while, yet, using enough of the pressure produced to move .the obturating sleeve into its sealing relation with less tendency for injurious impact against the barrel breech face. Also, lower pressure and lower 4 temperature producing powders can be used when the present invention is employed.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the'spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a gun of the type including a barrel and a drum having a projectile holding longitudinal chamber therein opening through opposite ends thereof in axial alignment with the bore of said barrel and with one end of said drum in normally spaced relation with the adjacent breech face of said barrel, a counterbore therein opening through 7 said pne end of said drum, meansv for sealing said chamher by bridging the space between said oneend of said drum and said adjacent breech face, said means com prising an obturating sleeve mounted within said counter bore for, movement longitudinally thereof, said chamber having at least one groove therein extending longitudinally thereof, said groove inclining downwardly and opening into said counterbore for conducting gases generated by the firing of a projectile in said chamber with the pressure of said. gases impinging upon one end of said sleeve remote, from said one end of the drum to move the sleeve longitudinally through said counterbore and into sealing relation with said breech face and bridge the space between said one end of the drum and said adjacent breech face of the barrel.

2. In a gun of the split chamber type including a barrelhaving, a breech face. at one end and a rotatable drum having a plurality of circumferentially spaced longitudinal chambers therein opening through opposite ends thereof and rotatable into axial alignment with the bore in said barrel, one end ofsaid drum being in normally spaced relation to the adjacent breech face-of said barrel, each of said chambers having a counterbore therein opening through said one end of'said drum, means for sealing said chamber by bridging the space between said one end ofthe drum and said breech face, said means comprising an obturating sleeve mounted in each of said counterbores for movement longitudinally thereof through said one end of the drum, each of said chambers having a plurality of circumferentially spaced grooves inclining downwardly and extending longitudinally thereof opening into said counterbore for conducting therethrough gases generated by the firing of a projectile in said chamber impinging upon one end of said sleeve remote from said one end of the chamber with less than the maximum pressure of said gases to move said sleeve longitudinally of its asso- I ciated counterbore through said one end of the drum into,

sealing relation with said breech face and bridge the space between said. one end of the drum and said adjacent breech face.

3. In a gun of the split chamber type including a barrel, having a breech. face at one end and a rotatable drum. having a plurality of circumferentially spaced longitudinal.

projectile carrying chambers therein opening through op.- posite ends thereof and rotatable into axial alignment with the bore in said barrel, one end of said drum being in normally spaced relation to the adjacent breech face of'said barrel, each of said chambers having a counterbore therein opening through said one end of said drum,

r means for sealing said chamber by bridging the space between said one end of the drum and said breech face, said means comprising an obturating sleeve mounted in each of said counterbores for movement longitudinally thereof through said one end of the drum, each of said chambers having a plurality of circumferentially spaced grooves extending longitudinally thereof opening into said counterbore for conducting therethrough gases generated by the firing of a projectile in said chamber im-v pinging upon one end of said sleeve remote from said one end of the chamber with less than the maximum pres sure of said gases to move said sleeve longitudinally of its associated counterbore through said one end of the drum into sealing relation with said breech face and bridge the space between said one end of the drum and said adjacent breech face, said grooves sloping from a point of zero depth at a location intermediate the ends of the chamber and substantially at a location at which the mouth of a projectile shell case is disposed when inserted into said chamber to a predetermined depth at the point where they open into said counterbore to define metering slots for determining the amount of the gas pressure generated to be utilized in moving said sleeve into its scaling relation with said breech face.

References Cited in the file of this patent UNITED STATES PATENTS 

